Several fixes for better displaying values.

WLAN_Thermometer.ino

@@ -24,7 +24,6 @@
 #define KRATE_TEMP            5000
 #define KRATE_TIME            500
 #define KRATE_RESET_AP_DATA   5000
-#define MEDIAN_SAMPLES        60
 #define ONBOARD_LED           2
 #define NTP_TIMEOUT           15000
 #define WIFI_CONNECT_TIMEOUT  30
@@ -46,6 +45,7 @@ const uint8_t degree_sign[8] = { B00010, B00101, B00010, B00000, B00000, B00000,
 uint8_t add_summertime = 0;
 bool last_reset_ap_check = false;
 bool minmax_enabled = false;
+char date_string_old[9];
 
 enum {
   ACT,
@@ -158,7 +158,9 @@ void setup()
   heat[MIN] = heat[ACT];
   heat[MAX] = heat[ACT];
 
-  lcd.clear();
+  strcpy(date_string_old, "--:--:----");
+
+  setup_screen();
   show_time();
   show_temperature();
 }
@@ -348,7 +350,8 @@ void check_reset_ap_data(void)
 
 void show_time(void)
 {
-  char dt[21];
+  char date_string[11];
+  char time_string[9];
 
   if (DateTime.isTimeValid())
   {
@@ -365,18 +368,29 @@ void show_time(void)
         add_summertime = 0;
     }
 
-    sprintf(dt, "%02d.%02d.%4d  %02d:%02d:%02d", p.getMonthDay(), p.getMonth() + 1, p.getYear(), p.getHours() + add_summertime, p.getMinutes(), p.getSeconds());
-    DEBUG_MSG("%s", dt);
+    sprintf(date_string, "%02d.%02d.%4d", p.getMonthDay(), p.getMonth() + 1, p.getYear());
+    sprintf(time_string, "%02d:%02d:%02d", p.getHours() + add_summertime, p.getMinutes(), p.getSeconds());
+
+    DEBUG_MSG("%s %s", date_string, time_string);
     if (add_summertime > 0)
       DEBUG_MSG(" Summertime\n");
     else
       DEBUG_MSG(" Wintertime\n");
   }
   else
-    sprintf(dt, "--:--:----  --:--:--");
+  {
+    strcpy(date_string, "--:--:----");
+    strcpy(time_string, "--:--:--");
+  }
 
-  lcd.setCursor(0, 0);
-  lcd.print(dt);
+  if (strcmp(date_string, date_string_old))
+  {
+    lcd.setCursor(0, 0);
+    lcd.print(date_string);
+    strcpy(date_string_old, date_string);
+  }
+  lcd.setCursor(12, 0);
+  lcd.print(time_string);
 
   digitalWrite(ONBOARD_LED, led_state);
   led_state = !led_state;
@@ -388,25 +402,50 @@ void show_temperature(void)
 
   DEBUG_MSG("Temperature: %02.2f\n", temp[ACT]);
 
-  lcd.setCursor(0, 1);
-  lcd.print("Temperatur:   ");
-  lcd.print(temp[ACT], 1);
-  lcd.write(0);
-  lcd.print("C");
+  lcd.setCursor(14, 1);
+  if (isnan(temp[ACT]))
+    lcd.print("--.-");
+  else
+    lcd.print(round_float(temp[ACT], 1), 1);
+
   if (millis() > FIRST_MIN_MAX)
   {
-    lcd.setCursor(0, 2);
-    lcd.print("Min: ");
-    lcd.print(temp[MIN], 1);
-    lcd.print("  Max: ");
-    lcd.print(temp[MAX], 1);
+    lcd.setCursor(5, 2);
+    if (isnan(temp[MIN]))
+      lcd.print("--.-");
+    else
+      lcd.print(round_float(temp[MIN], 1), 1);
+    lcd.setCursor(16, 2);
+    if (isnan(temp[MAX]))
+      lcd.print("--.-");
+    else
+      lcd.print(round_float(temp[MAX], 1), 1);
   }
+
+  lcd.setCursor(5, 3);
+  if (isnan(hum[ACT]))
+    lcd.print("--.-");
+  else
+    lcd.print(round_float(hum[ACT], 1), 1);
+  lcd.setCursor(16, 3);
+  if (isnan(heat[ACT]))
+    lcd.print("--.-");
+  else
+    lcd.print(round_float(heat[ACT], 1), 1);
+}
+
+void setup_screen(void)
+{
+  lcd.clear();
+  lcd.setCursor(0, 1);
+  lcd.print("Temperatur:");
+  lcd.setCursor(18, 1);
+  lcd.write(0);
+  lcd.print("C");
+  lcd.setCursor(0, 2);
+  lcd.print("Min: --.-  Max: --.-");
   lcd.setCursor(0, 3);
-  lcd.print("LF:  ");
-  lcd.print(hum[ACT], 1);
-  lcd.print("%");
-  lcd.print(" GT:  ");
-  lcd.print(heat[ACT], 1);
+  lcd.print("LF:     %  GT:");
 }
 
 bool is_wintertime(time_t t)
@@ -518,3 +557,8 @@ void ConfigAPStarted(WiFiManager * wm)
   lcd.clear();
   DEBUG_MSG("Config-AP started\n");
 }
+
+float round_float(float num, uint8_t dec_place)
+{
+  return ((round(num * powf(10, dec_place))) / powf(10, dec_place));
+}